Application of hypoglossal nerve constraint in definitive radiotherapy for nasopharyngeal carcinoma: A dosimetric feasibility study
Purpose: Radiation-induced hypoglossal nerve palsy is an infrequent but debilitating late complication after definitive radiotherapy for head and neck cancers. D1cc (Source: Medical Dosimetry)
Source: Medical Dosimetry - August 4, 2020 Category: Radiology Authors: James C.H. Chow, Jeffrey C.F. Lui, Kwok-Hung Au, Ka-Man Cheung, Roger K.C. Ngan, Alex K.C. Leung, Kenneth W.S. Li, Jeffrey C.H. Chan, Kam-Hung Wong, Francis K.H. Lee Source Type: research

Rationale for Using a C-Arm Fluoroscope to Deliver a Kilovoltage Radiotherapy Treatment to COVID-19 Patients
In 2013, Calabrese et al. described the effectiveness of early 20th century radiotherapy to treat viral and bacterial pneumonia patients, citing a cure rate of ∼80%.1 These were single fraction treatments of 30-100 cGy dose delivered with 100-200 kVp x-rays. These treatments stopped in the 1940s due to the availability of antibiotics and steroids, but in light of the lack of effective treatment options for COVID-19, radiotherapy could offer a viable and immediate option2,3 until a more effective cure becomes available. (Source: Medical Dosimetry)
Source: Medical Dosimetry - July 25, 2020 Category: Radiology Authors: D. Roa, H. Moyses, S. Leon, B. Hamrick, G. Sarria, T. Tajima, A. Necas, C. Guzman, O. Paucar, A. Gonzales, R. Challco, M. Montoya, Z. Arqque, A. Gonzales, J. Hernandez Source Type: research

Evaluation of a new GPU-enabled VMAT multi-criteria optimisation plan generation algorithm
To evaluate the new Varian, graphical processing unit (GPU)-enabled, volumetric-modulated arc therapy (VMAT) multi-criteria optimisation (MCO) tool for both its dosimetric accuracy and calculation time. This is a new capability within V16.0 and greater of the Varian Eclipse treatment planning system that allows VMAT optimisation and dose calculation using the GPU (termed GPU-VMAT). In versions prior to V16.0 VMAT multi-criteria optimisation calculations were only possible using central processing unit (CPU) (termed CPU-VMAT) and Hybrid-VMAT (H-VMAT). (Source: Medical Dosimetry)
Source: Medical Dosimetry - July 12, 2020 Category: Radiology Authors: Myles Spalding, Anthony Walsh, Trent Aland Source Type: research

A quantitative comparative study of medical dosimetry graduates with and without prior radiation therapy certification
All but a small number of formal medical dosimetry programs require radiation therapy certification for admission. The problem is a lingering perception from the radiation oncology community that medical dosimetry students must have a prior radiation therapy certification and/or experience. There is a paucity of evidence in the literature to support the perception that prior radiation therapy certification equates to better job performance as a medical dosimetrist. The purpose of this quantitative comparative study was to investigate outcomes of medical dosimetry graduates with and without prior radiation therapy certifica...
Source: Medical Dosimetry - July 10, 2020 Category: Radiology Authors: Nishele Lenards Source Type: research

Evaluation of replanning in intensity-modulated proton therapy for oropharyngeal cancer: Factors influencing plan robustness
The head and neck (H&N) region is frequently replanned during intensity-modulated proton therapy (IMPT), but replanning disrupts clinical workflow and presents additional burden on patients. The purpose of this study was to establish a standard treatment planning approach to minimize H&N replanning by identifying a correlation between dosimetric variables and replan frequency. In a retrospective study of 27 bilateral oropharyngeal cancer patients treated with IMPT at a single institution, cases were evaluated using Fisher's exact tests and logistic regression for a significant relationship between replan frequency ...
Source: Medical Dosimetry - July 10, 2020 Category: Radiology Authors: Noelle Deiter, Felicia Chu, Nishele Lenards, Ashley Hunzeker, Karen Lang, Daniel Mundy Source Type: research

Effects of gas-filled temporary breast tissue expanders on radiation dose from modulated rotational photon beams
This study therefore builds on previous investigations of the dosimetric effects of gas-filled TTEs in static photon and electron beams, by examining the effects of these implants on dose distributions from common modulated rotational treatment techniques; volumetric modulated arc therapy (VMAT) and helical tomotherapy (HT). (Source: Medical Dosimetry)
Source: Medical Dosimetry - July 10, 2020 Category: Radiology Authors: Tanya Kairn, Marika Lathouras, Michelle Grogan, Benjamin Green, Steven R. Sylvander, Scott B. Crowe Source Type: research

A format for dosimetry comparison studies
There is no standardized format for presenting and discussing the results of a radiotherapy dosimetry comparison study. The purpose of this report is to describe a format that we have found useful in evaluating plans in our department and in reviewing studies from other groups. (Source: Medical Dosimetry)
Source: Medical Dosimetry - July 8, 2020 Category: Radiology Authors: Robert J. Amdur, Roi Dagan, Adam Holtzman, Anamaria R. Yeung, Kathryn E. Hitchcock, William M. Mendenhall Source Type: research

Comparison of conventional and advanced radiotherapy techniques for left-sided breast cancer after breast conserving surgery
This study aims to compare seven WBRT techniques including conventional tangential, field-in-field (FIF), hybrid intensity-modulated radiotherapy (IMRT), IMRT, standard volumetric modulated arc therapy (STD-VMAT), noncoplanar VMAT (NC-VMAT), and multiple arc VMAT (MA-VMAT). Fifteen patients who were previously diagnosed with left-sided early stage breast cancer and treated in our clinic were selected for this study. (Source: Medical Dosimetry)
Source: Medical Dosimetry - July 6, 2020 Category: Radiology Authors: Yibo Xie, Daniel Bourgeois, Beibei Guo, Rui Zhang Source Type: research

Optimized stereotactic volumetric modulated arc therapy as an alternative to brachytherapy for vaginal cuff boost. A dosimetric study
We evaluate the role of stereotactic body radiotherapy using volumetric modulated arc therapy (VMAT) technique as an alternative to high-dose rate brachytherapy (HDR-BT) in the treatment of vaginal cuff in postoperative endometrial cancer. CT scans of 8 patients were used in this study. The clinical target volume (CTV) was defined as the 0.5 cm tissue around the applicator (then subtracting the applicator). Total dose was 30Gy delivered in 5 fractions. In HDR-BT, dose was prescribed at a distance of 0.5 cm from the surface applicator. (Source: Medical Dosimetry)
Source: Medical Dosimetry - June 19, 2020 Category: Radiology Authors: Savino Cilla, Gabriella Macchia, Giancarlo Mattiucci, Anna Ianiro, Carmela Romano, Milly Buwenge, Luigi Azario, Vincenzo Valentini, Francesco Deodato, Alessio G. Morganti Source Type: research

Flattening filter free beam energy selection and its impact in multitarget intracranial stereotactic radiosurgery treatments
This study aims to present a systematic dosimetric comparison of plan quality between 10 FFF vs 6 FFF beams in intracranial stereotactic radiosurgery (SRS) treatments using volumetric modulated arc therapy (VMAT). The dosimetric evaluation is based on radiation therapy oncology group (RTOG) dose conformity (CIRTOG) and gradient (GIRTOG) indices, and irradiated normal brain tissue volume. (Source: Medical Dosimetry)
Source: Medical Dosimetry - June 14, 2020 Category: Radiology Authors: Samir Laoui, Dante E. Roa, Jeffrey Kuo, Maxim Baldytchev, Jonathan Gonzales, Salam Dietrich, Nilam Ramsinghani, Parima Daroui, Hanako Farol Source Type: research

Evaluation of beam-on time and number of breath-holds using a flattening-filter-free beam with the deep inspiration breath-hold method in left-sided breast cancer
We performed a dosimetric study to evaluate the benefits of using a flattening-filter-free (FFF) beam with the deep inspiration breath-hold (DIBH) method for left-breast cancer. We used data from 30 previous patients with treatment plans that included DIBH for left-breast cancer with a flattened beam. FFF beam plans were calculated from previous treatment plan images and compared to the original plans in terms of monitor units (MU), number of segments, beam-on time, and breath-holds. Beam-on time was calculated by adding the traveling time of 1.5 second between segments to the time calculated from the MU and dose rate. (So...
Source: Medical Dosimetry - June 13, 2020 Category: Radiology Authors: Toru Takakura, Satoshi Koubuchi, Aiki Uehara, Ayano Tashima, Tomoyo Hirose, Hiroto Kimura, Seiji Tachiiri, Masahiko Koizumi Source Type: research

Dosimetric and planning efficiency comparison for lung SBRT: CyberKnife vs VMAT vs knowledge-based VMAT
This is the first study that compared treatment plan quality and planning efficiency for lung stereotactic body radiation therapy (SBRT) using CyberKnife (CK) Multiplan vs Varian Eclipse treatment planning systems, including volumetric modulated arc therapy (VMAT) and knowledge-based VMAT (KBP-VMAT). Thirteen lung SBRT patients treated with 50 to 55 Gy in 3 or 5 fractions were retrospectively included in this study. CK plans created with Multiplan V. 4.6.1 using 2 fixed circular cones were previously approved used for treatment. (Source: Medical Dosimetry)
Source: Medical Dosimetry - June 10, 2020 Category: Radiology Authors: Suhong Yu, Huijun Xu, Asa Sinclair, Xin Zhang, Ulrich Langner, Kimberley Mak Source Type: research

Dosimetric comparison of inverse and forward planning for Gamma Knife stereotactic radiosurgery of brain metastases
The Leksell GammaPlan (LGP) with an inverse planning (IP) tool has been upgraded to version 11.1 since its launch in 2010. We evaluated its IP planning performance by re-planning 16 targets that had been planned using forward planning (FP). The FP and IP plans were compared. A planning guideline for IP process was developed aiming for an unbiased comparison. Sixteen brain metastases (BMs) without nearby critical structures were included in the study (size> 1 cm for all targets). All prior FP were re-planned in the LGP using IP and maintaining the same beam-on time and coverage. (Source: Medical Dosimetry)
Source: Medical Dosimetry - June 7, 2020 Category: Radiology Authors: Qianyi Xu, Dershan Luo, David Mulvihill, Warren Goldman, Alan Turtz, Gregory J. Kubicek Source Type: research

Dosimetric effects of dose calculation grid size on the epidural space dose
Introduction: The epidural disease progression is the most common pattern of failure after spine stereotactic body radiotherapy. The aim of this study was to clarify the effect of the dose calculation grid size (CGS) during volumetric modulated arc therapy planning on the dose to the epidural space target. Materials and Methods: In the planning, the volume obtained by subtracting the planning organ at risk volume (PRV) of the spinal cord and/or cauda equina from the planning target volume (PTV) was defined as the PTVeval. (Source: Medical Dosimetry)
Source: Medical Dosimetry - June 7, 2020 Category: Radiology Authors: Hidetoshi Shimizu, Koji Sasaki, Hiroshi Tanaka, Takahiro Aoyama, Hiroyuki Tachibana, Yutaro Koide, Tohru Iwata, Tomoki Kitagawa, Takeshi Kodaira Tags: Research Article Source Type: research

A retrospective evaluation of mixed energy volumetric modulated arc therapy for anal cancers with lymph node involvement
Applying dual, or mixed photon energies during radiation therapy is a common practice in 3-dimensional conformal radiation therapy (3D-CRT). Mixed photon energies are used to provide uniform dose coverage to a planning target volume (PTV) that ranges in depth from the skin surface. Though the application of mixed photon energies in 3D-CRT was once the convention for treating anal cancers with lymph node involvement (AC-LNI), the advantages offered by volumetric modulated arc therapy (VMAT) prove to be the optimal form of therapy for AC-LNI. (Source: Medical Dosimetry)
Source: Medical Dosimetry - June 7, 2020 Category: Radiology Authors: Mikayla Eskens, Helen Nguyen, William Deere, Nishele Lenards, Ashley Hunzeker, Matt Tobler Source Type: research

OAR sparing 3D radiotherapy planning supported by fMRI brain mapping investigations
The human brain as an organ has numerous functions; some of them can be visualized by functional imaging techniques (e.g., functional MRI [fMRI] or positron emission tomography). The localization of the appropriate activity clusters requires sophisticated instrumentation and complex measuring protocol. As the inclusion of the activation pattern in modern self-tailored 3D based radiotherapy has notable advantages, this method is applied frequently. Unfortunately, no standardized method has been published yet for the integration of the fMRI data into the planning process and the detailed description of the individual applica...
Source: Medical Dosimetry - June 3, 2020 Category: Radiology Authors: G ábor Opposits, Csaba Aranyi, Csaba Glavák, Zsolt Cselik, Lajos Trón, Dávid Sipos, Janaki Hadjiev, Ervin Berényi, Imre Repa, Miklós Emri, Árpád Kovács Source Type: research

Robust treatment planning in whole pelvis pencil beam scanning proton therapy for prostate cancer
Whole-pelvis pencil beam scanning (PBS) proton therapy is utilized in both the intact and post-operative settings in patients with prostate cancer. As whole pelvis prostate radiotherapy has traditionally been delivered with standard photon beams, limited evidence and technical descriptions have been reported regarding the use of proton therapy. Here we present two robust three-field treatment planning approaches utilized to maximize target coverage in the presence of anatomic and delivery uncertainties. (Source: Medical Dosimetry)
Source: Medical Dosimetry - May 26, 2020 Category: Radiology Authors: Anish A. Butala, W. Scott Ingram, Shannon E. O'Reilly, Brett Hartl, Ali Kassaee, Curtiland Deville, Neha Vapiwala Source Type: research

Clinical evaluation of photon optimizer (PO) MLC algorithm for stereotactic, single-dose of VMAT lung SBRT
This report quantifies and compares the dosimetry and treatment delivery parameters of PO vs its predecessor progressive resolution optimizer (PRO) algorithm for a single-dose of volumetric modulated arc therapy (VMAT) lung stereotactic body radiation therapy (SBRT). Clinical SBRT treatment plans for 12 early-stage non –small-cell lung cancer patients receiving 30 Gy in 1 fraction using PRO-VMAT were re-optimized using the PO-VMAT MLC algorithm with identical planning parameters and objectives. (Source: Medical Dosimetry)
Source: Medical Dosimetry - May 19, 2020 Category: Radiology Authors: Justin Visak, Ronald C McGarry, Damodar Pokhrel Source Type: research

The degree of translational and rotational movement of implanted pacemakers and cardioverter-defibrillators on coronal plane images in patients treated with radiotherapy for lung malignancy
Malfunction of both implantable cardiac pacemakers and cardioverter-defibrillators as a result of exposure to therapeutic radiation is a known risk in radiation therapy. Although guidelines are available to minimize this risk for low energy beams, the guidelines rely on the estimated doses of ionizing radiation received by the device. Implicit in this calculation is that there is minimal day-to-day movement in the position of the device. However, with the exception of the leads in some cases, the devices are not intentionally sewn to the surrounding tissue but simply placed in a pocket in the prepectoral fascial compartmen...
Source: Medical Dosimetry - May 4, 2020 Category: Radiology Authors: Loukas A. Georgiou Source Type: research

Dosimetric and clinical advantages of adapting the DIBH technique to hybrid solitary dynamic portal radiotherapy for left-sided chest-wall plus regional nodal irradiation
To evaluate the dosimetric and clinical advantages of using deep-inspiration breath-hold (DIBH) technique in hybrid solitary dynamic portal radiotherapy (hSDPRT) for left-sided chest-wall plus regional nodal irradiation and to demonstrate a simplified strategy for preclinical commissioning and calibration of DIBH-gating technique. Fifteen patients with left-sided breast cancer who underwent postmastectomy radiotherapy using hSDPRT were retrospectively evaluated. Two sets of planning-CT images were acquired for each patient, one with free/normal breathing and the other with DIBH. (Source: Medical Dosimetry)
Source: Medical Dosimetry - May 3, 2020 Category: Radiology Authors: Kather Mohamathu Rafic, Solomon Patricia, Balasingh Timothy Peace, Christopher J. Sujith, Backianathan Selvamani, Paul B. Ravindran Source Type: research

The challenge of planning vertebral body SBRT: Optimizing target volume coverage
Stereotactic ablative body radiotherapy for vertebral metastases has been shown to be safe and effective to achieve tumor and pain control. To raise awareness of and build familiarity with vertebral stereotactic ablative body radiation therapy (SBRT) for a multicenter clinical trial including SBRT to vertebral metastases, Trans Tasman Radiation Oncology Cancer Research performed an international planning challenge. A single vertebral case was selected and the computed tomography image and contours were made available. (Source: Medical Dosimetry)
Source: Medical Dosimetry - April 12, 2020 Category: Radiology Authors: Nicholas Hardcastle, Fiona Bignell, Benjamin Nelms, Shankar Siva, Andrew Kneebone, Louis Lao, Olivia Cook, Monica Harris, John Shakeshaft Source Type: research

Atlas based segmentation in prone breast cancer radiation therapy
The evidence supporting atlas based contour generation is growing and includes breast, prostate, central nervous system, gastrointestinal, gynecologic, and head and neck cancer patient populations. We sought to investigate atlas based segmentation (ABS) in patients with early stage breast cancer status post breast conserving surgery treated with adjuvant radiation therapy in the prone position. An initial atlas library was generated by uploading 20 previously treated patients. Subsequently, a group of 20 consecutive patients underwent treatment planning. (Source: Medical Dosimetry)
Source: Medical Dosimetry - April 8, 2020 Category: Radiology Authors: William C. Stross, Steven M. Herchko, Laura A. Vallow Source Type: research

A dosimetric study using split x-jaw planning technique for the treatment of endometrial carcinoma
The aim of this retrospective study was to determine if the split x-jaw planning technique could be used with Varian linear accelerators to improve plan conformity and limit dose to organs at risk (OAR) for planning target volumes that require field sizes larger than the 15 cm extent of the multileaf collimator in the x-jaw position. Traditional planning techniques include limited and open x-jaw methods. The study population included 20 randomly selected patients with endometrial carcinoma. Treatment plans for each patient were designed using split, limited, and open x-jaw volumetric modulated arc radiotherapy for comparis...
Source: Medical Dosimetry - April 3, 2020 Category: Radiology Authors: Jeanette Keil, Joanne Carda, Jade Reihart, Marjorie Seidel, Nishele Lenards, Ashley Hunzeker Source Type: research

Exploiting tumor position differences between deep inspiration and expiration in lung stereotactic body radiation therapy planning
Purpose: We demonstrate proof of principle that normal tissue doses can be greatly reduced in lung stereotactic body radiation therapy (SBRT) for mobile tumors, if the delivered dose is split between opposite respiratory states. Methods: Patients that underwent 5 fraction lung SBRT at our institution and had deep inspiration breath hold (DIBH) and free breathing 4D computed tomography scans were included. Volumetric modulated arc therapy plans were generated on both respiratory phases and a third composite plan was generated delivering half the dose using the DIBH plan and the other half using the expiratory phase plan for...
Source: Medical Dosimetry - April 2, 2020 Category: Radiology Authors: Christina Huang, Kevin Shiue, Greg Bartlett, Namita Agrawal, Mona Arbab, Peter Maxim, Colleen DesRosiers, Todd Mereniuk, Susannah Ellsworth, Ryan Rhome, Jordan Holmes, Mark Langer, Richard Zellars, Tim Lautenschlaeger Source Type: research

Investigating the use of aperture shape controller in VMAT treatment deliveries
Background: Aperture shape controller (ASC) is a recently introduced leaf sequencer that controls the complexity of multileaf collimator apertures in the Photon Optimizer algorithm of the Eclipse treatment planning system. The aim of this study is to determine if the ASC can reduce plan complexity and improve verification results, without compromising plan quality. Methods: Thirteen plans grouped into cohorts of head and neck/brain, breast/chest and pelvis were reoptimised using the same optimization as the non-ASC setting for low, moderate and high ASC settings. (Source: Medical Dosimetry)
Source: Medical Dosimetry - March 26, 2020 Category: Radiology Authors: Diana Binny, Myles Spalding, Scott B. Crowe, David Jolly, Tanya Kairn, Jamie V. Trapp, Anthony Walsh Source Type: research

Dosimetric comparison of helical tomotherapy, volumetric-modulated arc therapy, intensity-modulated radiotherapy, and field-in-field technique for synchronous bilateral breast cancer
Purpose: To compare the dosimetric characteristics of helical tomotherapy (HT), volumetric-modulated arc therapy (VMAT), intensity-modulated radiotherapy (IMRT), and tangential field-in-field technique (FIF) for the treatment of synchronous bilateral breast cancer (SBBC). Methods and Materials: Ten patients with early-stage unilateral breast cancer were selected for simulating the patients with SBBC in this retrospective analysis. Treatment plans with HT, VMAT, IMRT, and FIF were generated for each patient with a total dose of 50.4 Gy in 28 fractions to the target. (Source: Medical Dosimetry)
Source: Medical Dosimetry - February 28, 2020 Category: Radiology Authors: Hao-Wen Cheng, Chih-Chieh Chang, An-Cheng Shiau, Ming-Hua Wang, Jo-Ting Tsai Source Type: research

Heart-sparing effect of postmastectomy radiotherapy for breast cancer patients: A dosimetric study of cardiac substructures
We investigated to what extent can the dose-volumes of the coronary artery and the cardiac substructures be reduced by using IMRT technique in left-sided breast cancer patients. We chose 40 pN2M0 patients treated with postmastectomy IMRT. The original treatment plans were retrieved and the (internal mammary nodes) IMNs and cardiac substructure delineations were added. Three sets of dose-volume parameters including the original plans without internal mammary irradiation (IMNI), the plans with IMNI, and the plans with dose constraints to the heart, were derived. (Source: Medical Dosimetry)
Source: Medical Dosimetry - February 25, 2020 Category: Radiology Authors: Fen Chen, Yee-Min Jen, Kui He, Zhaosheng Yin, Junwen Shi Source Type: research

Dosimetric evaluation of MR-derived synthetic-CTs for MR-only proton treatment planning
Purpose: To evaluate proton dose calculation accuracy of optimized pencil beam scanning (PBS) plans on MR-derived synthetic-CTs for prostate patients. Material and Methods: Ten patient datasets with both a CT and an MRI were planned with opposed lateral proton beams optimized to single field uniform dose under an IRB-approved study. The proton plans were created on CT datasets generated by a commercial synthetic CT-based software called MRCAT (MR for Calculating ATtenuation) routinely used in our clinic for photon-based MR-only planning. (Source: Medical Dosimetry)
Source: Medical Dosimetry - February 20, 2020 Category: Radiology Authors: David Aramburu N úñez, Sandra Fontenla, Lauren Rydquist, Gabriely Del Rosario, Zhiqiang Han, Chin-Cheng Chen, Dennis Mah, Neelam Tyagi Source Type: research

Evaluation of interbreath-hold lung tumor position reproducibility with vector volume histogram using the breath-hold technique
Tumor geometric reproducibility for lung stereotactic body radiotherapy (SBRT) is an important issue in the breath-hold (BH) technique. We investigated the inter-BH reproducibility of the tumor position in expiratory BH using our proposed vector volume histogram (VVH) method. Subjects comprising 14 patients with lung cancer who were treated with lung SBRT under expiratory BH conditions were monitored by the Abches system. Multiple computed tomography (CT) scans were performed to evaluate the inter-BH reproducibility of the tumor position at the expiratory BH in the simulation session. (Source: Medical Dosimetry)
Source: Medical Dosimetry - February 13, 2020 Category: Radiology Authors: Hideharu Miura, Shuichi Ozawa, Minoru Nakao, Yoshiko Doi, Katsumaro Kubo, Masahiko Kenjo, Yasushi Nagata Source Type: research

Confidence and proficiency levels of medical dosimetry graduates
The purpose of this study was to examine the confidence and proficiency levels of medical dosimetry graduates as they transition from student to professional during their first employment as medical dosimetrists. In addition, this study explored the support provided by employers to assist those medical dosimetry graduates during this transitional period. With assistance from the Medical Dosimetrist Certification Board (MDCB), individuals who graduated from a Joint Review Committee on Education in Radiologic Technology accredited medical dosimetry program between 2011 and 2018 and earned MDCB certification between 2012 and ...
Source: Medical Dosimetry - February 6, 2020 Category: Radiology Authors: Isaac D. Valdez, Kevin R. Clark Source Type: research

Evaluation of the effect of user-guided deformable image registration of thoracic images on registration accuracy among users
In this study, 4-dimensional computed tomographic images of 10 thoracic cancer patients were used. The dataset for these patients was provided by DIR-Lab (www.dir-lab.com) and included a coordinate list of anatomical landmarks (300 bronchial bifurcations). (Source: Medical Dosimetry)
Source: Medical Dosimetry - January 31, 2020 Category: Radiology Authors: Yujiro Nakajima, Noriyuki Kadoya, Takayuki Kanai, Masahide Saito, Satoshi Kito, Shimpei Hashimoto, Katsuyuki Karasawa, Keiichi Jingu Source Type: research

The comparison of VMAT test results for Clinac 2300C/D and TrueBeam accelerators
This study aimed to compare long-term VMAT performance QA on 3 accelerators: TrueBeam (TB) and 2 Clinacs (V4 and V5). All VMAT test plans were provided by Varian. (Source: Medical Dosimetry)
Source: Medical Dosimetry - January 30, 2020 Category: Radiology Authors: Agata Latala, Edyta Fujak, Agnieszka Walewska, Pawe ł Kukołowicz Source Type: research

Optimizing planning CT using past CT images for prostate cancer volumetric modulated arc therapy
This study aimed to evaluate a new method to optimize planning computed tomography (CT) using three-dimensional (3D) displacement error between the planning and diagnosed past CT scans. Thirty-two patients undergoing volumetric modulated arc therapy for prostate cancer were evaluated for a 3D displacement error between bone- and prostate-matching spatial coordinates using multiple acquisition planning CT (MPCT) scans. Each MPCT image and a past CT image were used to perform rigid image registration (RIR) and deformable image registration (DIR), and the 3D displacement error was calculated. (Source: Medical Dosimetry)
Source: Medical Dosimetry - January 30, 2020 Category: Radiology Authors: Yoshinori Tanabe, Takayuki Ishida, Hidetoshi Eto, Tatsuhiro Sera, Yuki Emoto Source Type: research

Dosimetric comparison of iPlan Ⓡ Pencil Beam (PB) and Monte Carlo (MC) algorithms in stereotactic radiosurgery/radiotherapy (SRS/SRT) plans of intracranial arteriovenous malformations
This study is a retrospective dosimetric comparison of iPlan Ⓡ Monte Carlo (MC) and Pencil Beam (PB) algorithms in SRS/SRT plans of cranial arteriovenous malformations (AVMs). PB plans of 60 AVM patients who were already treated using 6 MV photons from a linear accelerator were selected and divided into 2 groups. (Source: Medical Dosimetry)
Source: Medical Dosimetry - January 27, 2020 Category: Radiology Authors: Sharika Venugopal Menon, Raghukumar Paramu, Saju Bhasi, Zhenia Gopalakrishnan, Sarin Bhaskaran, Raghuram Kesavan Nair Source Type: research

A comparison of dose and set-up accuracy between flexed and extended neck positions in Helical Tomotherapy of nasopharyngeal carcinoma
This study investigated the dosimetric and set-up accuracy differences between these 2 set-up positions. Twenty NPC patients treated with HT from each set-up position were retrospectively recruited. HT plans were computed using the same target prescription and organs at risks (OARs) constraints for both set-up positions. The doses parameters of the target volumes and OARs were assessed. (Source: Medical Dosimetry)
Source: Medical Dosimetry - January 22, 2020 Category: Radiology Authors: Jason CP Lam, Vincent WC Wu, George Chiu, Pauline SW Kong, CM Wong Source Type: research

Dosimetric comparison between volumetric-modulated arc therapy and a hybrid volumetric-modulated arc therapy and segmented field-in-field technique for post-mastectomy chest wall and regional lymph node irradiation
(Source: Medical Dosimetry)
Source: Medical Dosimetry - January 17, 2020 Category: Radiology Source Type: research

Optimization of autogenerated chest-wall radiation treatment plans developed for postmastectomy breast cancer patients in underserved clinics
Over the past decade, several strides have been made to improve the management of breast cancer in developing countries; however, there are still obstacles present. In the area of radiation therapy, these hurdles include limited access to radiotherapy treatment and scarcity of oncology specialists. In an effort to reduce inequities in cancer care while improving patient outcomes, our research is focused on developing automated postmastectomy radiation therapy (PMRT) plans for breast cancer patients in these underserved communities that can be further improved upon through treatment planning system (TPS) specific optimizati...
Source: Medical Dosimetry - January 16, 2020 Category: Radiology Authors: Temiloluwa O. Esho, Christine V. Chung, Juanita U. Thompson, Mahsa Dehghanpour, Jordan R. Sutton, Simona F. Shaitelman, Kelly K. Kisling, Laurence E. Court Tags: 2019 Student Writing Competition —1st Place Source Type: research

MR-Linac Collimator Size Limitation and Impact on the Treatment of GYN Patients
(Source: Medical Dosimetry)
Source: Medical Dosimetry - January 13, 2020 Category: Radiology Source Type: research

Controlling heterogeneity within the lymphatic target volume for dose painted treatment of prostate cancer
We describe the creation of a control structure that can be incorporated into the optimization objective function. (Source: Medical Dosimetry)
Source: Medical Dosimetry - January 2, 2020 Category: Radiology Authors: Andrew M. McDonald, Robert S. Kirkland, Jared A. Mass, Allison P. Dalton Source Type: research

A sliding-window approach for improved VMAT dose calculation accuracy
The continuous delivery of volumetric modulated arc therapy (VMAT) plans is usually approximated by discrete apertures at evenly-spaced gantry angles for dose calculation purposes. This approximation can potentially lead to large dose calculation errors if the gantry angle spacings are large and/or there are large changes in the MLC apertures from one control point (CP) to the next. In this work, we developed a sliding-window (SW) method to improve VMAT dose calculation accuracy. For any 2 adjacent VMAT CPs ni and ni  + 1, the dose distribution was approximated by a 2-CP SW IMRT beam with the starting MLC positions at ...
Source: Medical Dosimetry - December 31, 2019 Category: Radiology Authors: Haitham N Alahmad, Ji-Yeon Park, Nicholas J Potter, Bo Lu, Guanghua Yan, Chihray Liu, Jonathan G Li Source Type: research

Proton pencil beam scanning treatment with feedback based voluntary moderate breath hold
Introduction The aim of this article is to introduce a novel protocol for proton pencil beam scanning treatment with moderate deep inspiration breath hold (mDIBH) and report on our clinical implementation results. Methods Three computed tomography (CT) scannings to build the patient's anatomy model were performed during the patient's voluntary mDIBH. All 3 CT scans were used in the optimization during the treatment planning process. Both orthogonal kV imaging and cone-beam computed tomography (CBCT) were implemented for patient alignment with BH prior to the treatment. (Source: Medical Dosimetry)
Source: Medical Dosimetry - December 20, 2019 Category: Radiology Authors: Peng Wang, Shikui Tang, Karla Leach, Victor Mangona, Charles B. Simone, Katja Langen, Chang Chang Source Type: research

Small bowel dose in subserosal tandem insertion during cervical cancer brachytherapy
In this study, we aimed to quantify and further predict individual SB dose increase and to increase focus on the SB in subserosal tandem insertions. Images and dosimetry data of cervical cancer brachytherapy with subserosal insertion (SI) were reviewed. The percentage increases in the SB dose compared with intracavitary insertion (II) at 8 points of D(x)cc with 10 cc intervals were assessed. (Source: Medical Dosimetry)
Source: Medical Dosimetry - December 18, 2019 Category: Radiology Authors: Yu-Lun Tsai, Pei-Chieh Yu, Louis Tak Lui, Suzun Shaw, Ching-Jung Wu Source Type: research

Functional cranio-spinal irradiation: A hippocampal and hypothalamic-pituitary axis sparing radiation technique using two IMRT modalities
In this study, we compared the efficacy of Volumetric Modulated Arc Therapy (VMAT) and Helical Tomotherapy (HT) in delivering this n ovel CSI technique. (Source: Medical Dosimetry)
Source: Medical Dosimetry - December 13, 2019 Category: Radiology Authors: Jack Zheng, Saif Aljabab, Patricia Lacasse, Jamie Bahm, Katie Lekx-Toniolo, Laval Grimard Source Type: research

Optimization of the accelerated partial breast brachytherapy fractionation considering radiation effect on planning target and organs at risk
The same fractionation scheme of accelerated partial breast irradiation (APBI) with brachytherapy is usually applied to APBI patients without considering the radiaton effect on the planning target and organs at risk (OARs) for an individual patient. The purpose of this study is to report the results of optimization of the fractionation scheme by evaluating the radiation effect on target and OARs with a modified linear-quadratic model, universal survival curve (USC), based on dose-volume histograms (DVHs). (Source: Medical Dosimetry)
Source: Medical Dosimetry - December 7, 2019 Category: Radiology Authors: Weihua Fu, Mohammed Saiful Huq Source Type: research

The mean absolute dose deviation –A common metric for the evaluation of dose-volume histograms in radiation therapy
Radiation therapy needs to balance between delivering a high dose to targets and the lowest possible dose to the organs at risk. Dose-volume histograms (DVHs) summarize the distribution of radiation doses in the irradiated structures. The interpretation can however be a challenge when the number of structures is high. We propose the use of a simple summary metric. We define the mean absolute dose deviation (MADD) as the average of absolute differences between a DVH and a reference dose. The properties are evaluated through numerical analysis. (Source: Medical Dosimetry)
Source: Medical Dosimetry - November 19, 2019 Category: Radiology Authors: Vincent Vinh-Hung, Nicolas Leduc, Dirk Verellen, Claire Verschraegen, Giovanna Dipasquale, Nam P. Nguyen Source Type: research

RapidPlan development of VMAT plans for cervical cancer patients in low- and middle-income countries
Cervical cancer has a high incidence and mortality rate in low- and middle-income countries (LMICs) largely due to limited resources and insufficient staffing. Knowledge-based planning (KBP) could alleviate understaffing issues by streamlining the radiotherapy treatment planning process. Varian's KBP system (RapidPlan) was used to develop a model capable of producing volumetric modulated arc therapy (VMAT) plans for cervical cancer patients. Plan data from 46 patients previously treated at MD Anderson Cancer Center (MDACC) were used to create and train the model which was then applied to 32 patients excluded from the train...
Source: Medical Dosimetry - November 15, 2019 Category: Radiology Authors: Marisol Tinoco, Erika Waga, Kevin Tran, Hieu Vo, Jamie Baker, Rachel Hunter, Christine Peterson, Nicolette Taku, Laurence Court Source Type: research

Comparison of dose distributions between transverse magnetic fields of 0.35  T and 1.5 T for radiotherapy in lung tumor using Monte Carlo calculation
We investigated the impact of the transverse magnetic fields of 0.35 T and 1.5 T on the dose distributions for a 6 MV beam, by using a thorax phantom with a lung tumor. First, the dose distributions in the magnetic flux densities of 0 T, 0.35 T, and 1.5 T were compared by increasing the number of irradiation fields. Next, the dose distributions for stereotactic body radiotherapy (SBRT) with 5-fields for an isolated lung tumor was compared in transverse magnetic fields. All dose distributions were calculated by the Monte Carlo method. (Source: Medical Dosimetry)
Source: Medical Dosimetry - November 15, 2019 Category: Radiology Authors: Takahiro Kubota, Fujio Araki, Takeshi Ohno Source Type: research

Improving TBI lung dose calculations: Can the treatment planning system help?
Lung toxicity is a serious concern during total body irradiation (TBI). Therefore, evaluation of accurate dose calculation when using lung blocks is of utmost importance. Existing clinical treatment planning systems can perform the calculation but there are large inaccuracies when calculating volumetric dose at extended distances in the presence of high atomic number materials. Percent depth dose and absolute dose measurements acquired at 400 cm SSD with a cerrobend block were compared with calculated values from the Eclipse treatment planning system using AAA and Acuros. (Source: Medical Dosimetry)
Source: Medical Dosimetry - November 12, 2019 Category: Radiology Authors: Narottam Lamichhane, Matthew T. Studenski Source Type: research

Surface dose and acute skin reactions in external beam breast radiotherapy
The biologically relevant depth for acute skin reactions in radiotherapy is 70 µm. The dose at this depth is difficult to measure or calculate and can be quite different than the dose at a depth of as little as 1 mm. For breast radiotherapy with medial and lateral tangential beams, the skin dose depends on both the contribution from the entrance beam and the exit beam. The sk in dose has been estimated in a breast model hemi-ellipse accounting for field size, beam energy, obliquity, lack of backscatter, fractionation, size and shape of the hemi-ellipse. (Source: Medical Dosimetry)
Source: Medical Dosimetry - November 9, 2019 Category: Radiology Authors: Patrick N. McDermott Source Type: research

Evaluation of the RayStation electron Monte Carlo dose calculation algorithm
The aim of this work was to evaluate the accuracy of the RayStation treatment planning system electron Monte Carlo algorithm against measured data for a range of clinically relevant scenarios. This was done by comparing measured percentage depth dose data (PDD) in water, profiles at oblique incidence and with heterogeneities in the beam path, and output factor data and that generated using the RayStation treatment planning system Monte Carlo VMC++ based calculation algorithm. While electron treatments are widely employed in the radiotherapy setting accurate modelling is challenging (TPS) in the presence of patient being bo...
Source: Medical Dosimetry - October 17, 2019 Category: Radiology Authors: Neil Richmond, Vincent Allen, Jonathan Wyatt, Richard Codling Source Type: research